1. Field of the Invention
The present invention relates generally to the field of fiber optics, and particularly to advantageous aspects of systems and methods for reducing splice loss in optical fibers.
2. Description of Prior Art
When optical fibers are spliced together, a certain amount of splice loss typically results. Because of the increasing demands being placed on optical fiber transmission systems, the problem of splice loss has become increasingly significant. Techniques have been developed to reduce splice loss. However, such techniques typically focus on refinements to the splicing operation, or on post-splice treatments of spliced fibers.
The prior art includes descriptions of optical fibers with specific viscosity characteristics. See, for example, M. Tateda et al., xe2x80x9cDesign of Viscosity-Matched Optical Fibers,xe2x80x9d IEEE Photonics Technology Letters, Vol. 4, No. 9, pp. 1023-25 (1992). In one described design, residual elastic stress is reduced in order to reduce Rayleigh scattering losses. S. Sakaguchi et al., xe2x80x9cViscosity of Silica Core Optical Fiber,xe2x80x9d Journal of Non-Crystalline Solids, Vol. 244, pp. 232-73 (1999).
Aspects of the invention provide optical fibers exhibiting reduced splice loss and methods for making same. An optical fiber according to an aspect of the invention comprises a plurality of regions, one region having a higher viscosity and the other region having a lower viscosity, such that when the fiber is drawn under tension, a strain is frozen into the higher viscosity region. A lower viscosity buffer layer is sandwiched between the higher viscosity region and the lower viscosity region. The buffer layer isolates the lower viscosity region from changes in refractive index in the higher viscosity region arising from a change in the strain frozen into the higher viscosity region.
Additional features and advantages of the present invention will become apparent by reference to the following detailed description and accompanying drawings.